A bypass has the advantage of allowing part of the flow to be rerouted, without thereby disadvantaging the loss in pressure in the main circuit part. It is thus possible to obtain, in the case of motor vehicles, for example, a more rapid increase in the temperature of the fluid during starting. If the flow of fluid issuing from the engine is diverted towards a short-circuit loop fitted directly to the engine, a low volume of fluid passes through this loop, which causes the temperature of the fluid to rise rapidly. Then, once the fluid has reached a predetermined temperature, it may be provided to remove this bypass.
A water outlet chamber that is intended to direct the flow in a transverse direction, so as to be able to direct it towards a supplementary branch of a circuit, as well as in the longitudinal direction of the chamber, is presented in French patent application No. 03 15 204, in the name of the Applicant. Said chamber also comprises an opening formed in its constituent lateral wall, and contains an insert forming a conduit part inside the component, one of the end openings of which insert is located opposite and adjacent to said lateral opening, in the assembly position of said insert.